NADPH Phagocyte Oxidase Knockout Mice Control Trypanosoma cruzi Proliferation, but Develop Circulatory Collapse and Succumb to Infection

•NO is considered to be a key macrophage-derived cytotoxic effector during Trypanosoma cruzi infection. On the other hand, the microbicidal properties of reactive oxygen species (ROS) are well recognized, but little importance has been attributed to them during in vivo infection with T. cruzi. In order to investigate the role of ROS in T. cruzi infection, mice deficient in NADPH phagocyte oxidase (gp91phox−/− or phox KO) were infected with Y strain of T. cruzi and the course of infection was followed. phox KO mice had similar parasitemia, similar tissue parasitism and similar levels of IFN-γ and TNF in serum and spleen cell culture supernatants, when compared to wild-type controls. However, all phox KO mice succumbed to infection between day 15 and 21 after inoculation with the parasite, while 60% of wild-type mice were alive 50 days after infection. Further investigation demonstrated increased serum levels of nitrite and nitrate (NOx) at day 15 of infection in phox KO animals, associated with a drop in blood pressure. Treatment with a NOS2 inhibitor corrected the blood pressure, implicating NOS2 in this phenomenon. We postulate that superoxide reacts with •NO in vivo, preventing blood pressure drops in wild type mice. Hence, whilst superoxide from phagocytes did not play a critical role in parasite control in the phox KO animals, its production would have an important protective effect against blood pressure decline during infection with T. cruzi

A novel antimicrobial lectin from Eugenia malaccensis that stimulates cutaneous healing in mice model

Objective The present work reports the purification and partial characterization of an antibacterial lectin (EmaL) obtained from Eugenia malaccensis seeds as well as the evaluation of its effect in the daily topical treatment of repairing process of cutaneous wounds in mice. Materials and methods The cutaneous wound was produced by the incision of the skin and use of lectin in the treatment of mice cutaneous wounds was evaluated. Surgical wounds were treated daily with a topical administration of EmaL and parameters such as edema, hyperemia, scab, granulation and scar tissues as well as contraction of wounds were analyzed. Results A novel lectin, with a molecular mass of 14 kDa, was isolated from E. malaccensis using affinity chromatography. The lectin (EmaL) agglutinated glutaraldehyde-treated rabbit and human erythrocytes; the lectin-induced rabbit erythrocyte agglutination was inhibited by glucose, casein, ovalbumin and fetuin. Also, Emal was very effective in the inhibition of bacterial growth, with the best inhibition results obtained for Staphylococcus aureus. Inflammatory signals such as edema and hyperemia were statistically less intense when EmaL was applied compared to the control. The histopathological analysis showed that the treated injured tissue presented reepithelialization (complete or partial) and areas of transition more evidenced than those of the control group, especially due to well organized pattern of collagen fibers presented in the granulation fibrous tissue. Conclusion Presented results are a preliminary indication of the pharmacological interest in using EmaL as antimicrobial agent and in the repairing process of cutaneous wounds.This paper was financially supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), FACEPE and CAPES, Brazil. The authors are deeply grateful for the technical assistance of Maria Barbosa Reis da Silva and João Antonio Virgínio and Alfa/VALNATURA Project.info:eu-repo/semantics/publishedVersio